Automatic control for grain driers

Claim 1

A drier for grain or the like comprising: a. a generally vertical column through which said grain falls, said column having spaced-apart parallel perforated walls containing a hot upper portion and a cool lower portion; b. means for removing said grain from below said cool portion at a substantially constant speed; adjusted c. heater means for heating air; d. means for guiding hot air from said heater means to said hot upper portion; e. cold air inlet means for guiding cold air into said cool lower portion; f. fan means for forcing said hot air through said hot air guide means and through said hot upper portion to heat said grain thereby reducing the moisture content of said grain, and for forcing said cold air through said cool lower portion to cool said grain after said grain has passed through said hot upper portion; g. drier control means comprising: i. temperature probe means in said hot upper portion adjacent said cool lower portion and responsive to the temperature of said grain; ii. control means operatively connected to said probe means for continuously comparing said grain temperature with a predetermined grain temperature corresponding to a required grain moisture content; and iii. control valve means operatively connected to said control means and to said heater means for adjusting the flow of fuel to said air heater means as said grain temperature varies from said predetermined temperature, to thereby adjust said hot air temperature and maintain said grain at substantially said predetermined temperature corresponding to said moisture content.